US6735283B2 - Rotating anode X-ray tube with meltable target material - Google Patents

Rotating anode X-ray tube with meltable target material Download PDF

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Publication number
US6735283B2
US6735283B2 US10/255,977 US25597702A US6735283B2 US 6735283 B2 US6735283 B2 US 6735283B2 US 25597702 A US25597702 A US 25597702A US 6735283 B2 US6735283 B2 US 6735283B2
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Prior art keywords
anode
ray tube
rotary body
rotating anode
cathode
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Expired - Fee Related, expires
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US10/255,977
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US20030058995A1 (en
Inventor
Wolfgang Kutschera
Eberhard Lenz
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Siemens AG
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Siemens AG
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Assigned to SIEMENS AKTIENGESELLSCHAFT reassignment SIEMENS AKTIENGESELLSCHAFT ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: KUTSCHERA, WOLFANG, LENZ, EBERHARD
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J35/00—X-ray tubes
    • H01J35/02—Details
    • H01J35/04—Electrodes ; Mutual position thereof; Constructional adaptations therefor
    • H01J35/08—Anodes; Anti cathodes
    • H01J35/10—Rotary anodes; Arrangements for rotating anodes; Cooling rotary anodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2235/00—X-ray tubes
    • H01J2235/08—Targets (anodes) and X-ray converters
    • H01J2235/081—Target material
    • H01J2235/082—Fluids, e.g. liquids, gases

Definitions

  • the present invention is directed to a rotating anode X-ray tube suitable for use as a high-power X-ray tube for use in CT (computed tomography) installations.
  • the focal path of the target i.e. the anode surface onto which the electron beams emitted by the cathode are incident
  • This wear leads to a modification of the spectral composition of the X-rays, which usually are emitted in a flat angle.
  • the usable X-ray dose is diminished because of the radiation emitted at the flat angle.
  • Another problem arises due to the stripping of particles from the focal path because increased arcing can occur in the X-ray tube.
  • German Patent 890 246 discloses a rigidly arranged anode wherein the focal path of the anode be fashioned as a circulating metallic liquid. Such a fashioning is supposed to have the advantage that the focal spot is constantly replenished and that the X-ray tube can be placed under a substantially greater load.
  • Mercury is cited as liquid in the this reference, this being arranged in an evacuated, closed vessel of, for example, glass.
  • the vessel is placed into rotation by means of a rotating electromagnetic field, and the metallic liquid forms a paraboloid of revolution upon rotation under the influence of the rotating field.
  • An opening through which the electrons coming from the cathode can proceed onto the outside surface of the mercury body is situated in the wall of the vessel that accepts the metallic liquid.
  • the X-ray beam generated in this way has the approximate shape of a cone.
  • a collecting device is provided for collecting the mercury that splatters through this opening during rotation, this collecting device also having a space for the condensation of the mercury vapor.
  • An object of the present invention is to provide a rotating anode X-ray tube that, in particular, can be used as a high-power tube in a CT installation, with which the aforementioned disadvantages are avoided and with which, in particular, the service life of the anode can be lengthened in an economical way.
  • a rotating anode X-ray tube particularly of the type suitable for use in CT installations, having a housing with a cathode rigidly arranged therein and an anode rotatably arranged therein, and wherein the anode has a focal path composed of target material that melts during operation of the tube, and wherein, when the target material is in a molten state, it is held to the anode by a rotary body due to centrifugal forces of the rotary body when rotating around the cathode.
  • the invention is based on the perception of melting the focal path of the anode during operation and thus constantly smoothing it, i.e. keeping it smooth during operation.
  • the rotary body is designed such that the centrifugal forces hold the molten material in place and simultaneously prevent the formation of a parabolic surface.
  • the inventive anode X-ray tube is comparatively simple to fashion in terms of design and requires no collecting vessel as in the aforementioned known tubes.
  • the anode is arranged at a rotary body that has an annular focal path.
  • the rotary body can be cylindrical or funnel-like, and the anode with the focal path is arranged at the expanded end of the rotary body given the latter design.
  • Tungsten can be provided as the target material to be melted. Since, however, tungsten already has a vapor pressure above its melting point that could lead to arcing and emission problems given a standard design of a cathode/anode arrangement, a eutectic tungsten alloy having a melting point below that of tungsten and having a vapor pressure of ⁇ 0.1 hPa in the environment of the melting temperature is advantageously employed.
  • the following elements are suitable as further materials for the focal path to be melted during operation: tantalum (Ta), osmium (Os), ruthenium (Ru), molybdenum (Mo), niobium (Nb), rhodium (Rh), thorium (Th), palladium (Pd), gold (Au), iridium (Ir), rhenium (Re), platinum (Pt), hafnium (Hf), lanthanum (La).
  • An alloy system of subsets of these elements or boride or carbide compounds of said elements can also be advantageously applied.
  • the cathode and anode are shielded from one another by partitions and that the cathode thus is protected against vapors from the anode material.
  • the partitions are advantageously provided with a diaphragm in the region of the beam passage that blocks the vapor pressure but is largely transmissive for electrons having kinetic energies that typically lie above approximately 60 keV in this application.
  • Such a version has the advantage that even pure tungsten can be employed as the meltable target material; in particular, materials having higher vapor pressures, and thus materials having higher melting temperatures than, for example, tungsten, can be permitted.
  • FIG. 1 is a side sectional view of a first embodiment of a rotating anode Xray tube according to the invention
  • FIG. 2 is a side sectional view of a portion of a second embodiment of a rotating anode X-ray tube of the invention.
  • FIG. 3 illustrates a modification of the embodiment according to FIG. 2 .
  • FIG. 4 illustrates a modification of the embodiment according to FIG. 1 .
  • FIG. 1 shows a simplified illustration of a first embodiment of a rotating anode X-ray tube of the invention.
  • the rotating anode X-ray tube is suitable for use as a high-power X-ray tube for use in CT installations.
  • the rotating anode X-ray tube contains a vacuum housing 2 in which a cathode 3 is arranged such that its emitter 4 —as indicated by an arrow—can radially emit electrons.
  • the vacuum housing 2 can be composed of glass, metal or ceramic. In the case of a metallic embodiment, care must be exercised so that the cathode 3 is electrically separated from the vacuum housing 2 by means of an appropriate insulation 5 .
  • the emitter 4 can be implemented as a flat emitter; alternatively it can be helical.
  • a rotary body 6 is rotatably seated in the vacuum housing 2 concentrically with the symmetry axis 1 .
  • the bearing of the rotary body is referenced 7 in general and can be formed by rolling bearings that axially and radially support the bearing neck (not referenced in detail) of the rotary body 6 .
  • An electrical drive 8 is provided in order to be able to place the rotating anode arrangement into rotation, the drive 8 including a rotor 9 of electrically conductive material (Cu) rigidly connected to the rotary body 6 and a stator 10 arranged outside the vacuum housing 2 .
  • the stator 10 and the rotor 9 form a squirrel-cage motor that drives the rotary body 6 with a typical frequency of 150 Hz.
  • the rotary body 6 Facing away from the drive 8 , the rotary body 6 is fashioned funnel-like or conical and carries the anode 11 at its free end.
  • the funnel-shaped design of the rotary body 6 is advantageous because it enables a space-saving accommodation of the cathode 3 , it is not compulsory in this form.
  • Other embodiments of the rotary body 6 are also conceivable and within the scope of the invention, for example in the form of a cylindrical tube that accepts the anode at one end and the bearing for the drive at its other end.
  • the anode 11 is annular and surrounds the cathode 3 . Facing toward the cathode 3 , the anode 11 contains a focal path 12 of meltable target material.
  • melttable target material means a material that changes from the solid into the liquid solid state due to the heating of the anode 11 (typically to approximately 2800° C.) during operation of the tube and changes vice versa after the tube is turned off.
  • the anode 11 contains a carrier part 13 composed of a material that does not melt during operation of the tube.
  • the latter can be composed of ceramic or graphite, preferably fiber reinforced carbon.
  • Further advantageous materials are standard refractory metals such as molybdenum (Mo), heat-resistant molybdenum alloys, osmium (Os), tungsten (W), rhenium (Re), rhodium (Rh), tantalum (Ta), niobium (Nb), ruthenium (Ru), vanadium (V) and boron (B).
  • the focal path 12 that melts during operation is composed of an approximately 0.5 through 3 mm thick layer of tungsten or tungsten carbide or of some other suitable material that melts during operation of the tube, for example from the chemical group of carbides or borides or of one of the aforementioned elements. This layer is applied onto the carrier part 13 .
  • the carrier part 13 is provided with a suitably fashioned edge 15 .
  • the edge 15 is radially directed toward the symmetry axis and may slant slightly inwardly. The target material, which melts during operation of the tube, is thus bonded to the carrier part 13 of the anode and emergence from the target is prevented.
  • the anode 11 is arranged with reference to the cathode 3 so that the X-rays are emitted at a flat angle ⁇ and can emerge through a beam exit window 14 peripherally arranged in the vacuum housing 2 .
  • the beam path of the X-rays proceeds at about 45° relative to the plane of the drawing.
  • the X-rays are conducted through the cathode holder 16 .
  • a beam passage window 17 acting a pre-diaphragm is arranged in the holder 16 .
  • a reduction of the extra-focal radiation can be achieved with such an arrangement.
  • a suitable heat store 18 is provided at least in the region of the anode 11 , expediently in the entire region of the cone of the rotary body 6 .
  • the heat store 18 is capable of intermediately storing the heat that arises during operation of the tube for a short time.
  • a graphite layer of about 10 through 30 mm that is soldered onto the rotary body 6 has proven advantageous such as a heat store.
  • the anode 11 is fashioned such that the X-rays can pass through the carrier part 13 in the arrow direction.
  • Such an embodiment has a higher efficiency than the version previously explained.
  • the beam exit window 14 also is peripherally arranged at the vacuum housing 2 as an extension of the radial emission of the electrons.
  • the carrier part 13 is composed of material that is transmissive for X-rays, for example ceramic, graphite or of suitable borides.
  • the target layer applied on the carrier part 13 preferably lies in the range from a few ⁇ m to a maximum of approximately 10 ⁇ m.
  • a blocking layer 19 of up to 20 ⁇ m thickness of material that does not melt during operation can be applied between the target layer and the carrier part 13 .
  • FIG. 3 shows a further version of a rotating anode X-ray tube wherein partitions 20 are provided between the cathode 3 and the anode 11 . These partitions protect the cathode from ion bombardment and the penetration of vapors of anode material.
  • the partitions 20 can be part of the vacuum housing and are provided with the diaphragm 21 in the region of the beam passage, said diaphragm 21 being largely transmissive for electrons above, for example, 60 keV but blocking against vapor pressure up to a relatively high vapor pressure of, for example, >1 hPa (dependent on the operating temperature and the selected target material).
  • this version has the advantage that materials having relatively high vapor pressures can be selected as the meltable target material, or that the electron beam power can be increased in the case of tungsten or rhenium (or similar refractory metals).
  • FIG. 4 shows a version wherein the exit of the X-rays—as described for the version according to FIG. 1 —ensues laterally at a flat angle a but wherein the cathode does not lie directly within the rotation region of the anode 11 .
  • the cathode 3 with the cathode holder 22 is arranged somewhat outside the rotation region.
  • a diaphragm 23 that is carried by a holder 24 secured to the vacuum housing 2 is arranged in the beam path of the electron emission.
  • the diaphragm 23 is of such a nature that it lets electrons through but prevents the passage of ions.
  • the diaphragm holder 24 is electrically conductively connected to the vacuum housing 2 and lies at the same potential as the rotary body 6 , preferably at ground.
  • the space between the target and the diaphragm 23 thus is kept free of potential, having the advantage that no arcing can occur given briefly higher vapor pressures in the target region.
  • the emitter of the cathode 3 also is protected against increased ion bombardment.

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  • X-Ray Techniques (AREA)
US10/255,977 2001-09-25 2002-09-26 Rotating anode X-ray tube with meltable target material Expired - Fee Related US6735283B2 (en)

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DE10147473A DE10147473C2 (de) 2001-09-25 2001-09-25 Drehanodenröntgenröhre
DE10147473.3 2001-09-26
DE10147473 2001-09-26

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Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040120463A1 (en) * 2002-12-20 2004-06-24 General Electric Company Rotating notched transmission x-ray for multiple focal spots
US20050286684A1 (en) * 2004-06-25 2005-12-29 Mathias Hornig Rotary piston x-ray tube with the anode in a radially rotating section of the piston shell
US20060146985A1 (en) * 2004-11-19 2006-07-06 Thomas Deutscher Leakage radiation shielding arrangement for a rotary piston x-ray radiator
US20070177715A1 (en) * 2004-03-19 2007-08-02 Geoffrey Harding Electron window for a liquid metalanode, liquid metal anode, x-ray emitter and method for operating such an x-ray emitter of this type
US20070258563A1 (en) * 2004-01-20 2007-11-08 Geoffrey Harding Anode Module for a Liquid Metal Anode X-Ray Source, and X-Ray Emitter Comprising an Anode Module
DE102012203807A1 (de) * 2012-03-12 2013-09-12 Siemens Aktiengesellschaft Röntgenröhre
US8983037B2 (en) 2009-09-30 2015-03-17 Koninklijke Philips N.V. Balancing of the rotary anode of an X-ray tube
WO2016010448A1 (en) 2014-07-17 2016-01-21 Siemens Aktiengesellschaft Fluid injector for x-ray tubes and method to provide a liquid anode by liquid metal injection
US9257255B2 (en) 2013-08-08 2016-02-09 Siemens Aktiengesellschaft Single-pole x-ray emitter
EP3926656A4 (de) * 2019-04-26 2022-05-04 EUV Labs Ltd. Röntgenstrahlquelle mit rotierendem flüssigmetallziel

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US7194066B2 (en) * 2004-04-08 2007-03-20 General Electric Company Apparatus and method for light weight high performance target
JP4273059B2 (ja) * 2004-08-20 2009-06-03 志村 尚美 Ｘ線発生方法及びｘ線発生装置
US7653178B2 (en) * 2004-08-20 2010-01-26 Satoshi Ohsawa X-ray generating method, and X-ray generating apparatus
JP2007066850A (ja) * 2005-09-02 2007-03-15 Tomohei Sakabe Ｘ線発生方法及びｘ線発生装置
JP5006737B2 (ja) * 2007-08-28 2012-08-22 知平 坂部 回転対陰極ｘ線発生装置及びｘ線発生方法
DE102008006620A1 (de) * 2008-01-29 2009-08-06 Smiths Heimann Gmbh Röntgenstrahlerzeuger sowie dessen Verwendung in einem Röntgenuntersuchungs- oder Röntgenprüfgerät
DE102008026633A1 (de) * 2008-06-04 2009-12-10 Siemens Aktiengesellschaft Röntgenröhre
DE102008032995A1 (de) * 2008-07-14 2010-01-21 Siemens Aktiengesellschaft Röntgenröhre
DE102009033607A1 (de) * 2009-07-17 2011-01-20 Siemens Aktiengesellschaft Röntgenröhre und Anode für eine Röntgenröhre
WO2012080958A2 (en) 2010-12-16 2012-06-21 Koninklijke Philips Electronics N.V. Anode disk element with refractory interlayer and vps focal track
DE102014221931B4 (de) * 2014-10-28 2023-05-25 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Röntgenröhre sowie Vorrichtung und Verfahren zur Emission von Röntgenstrahlung
RU2617840C2 (ru) * 2016-06-16 2017-04-28 Общество с ограниченной ответственностью "Микрофотоника" Рентгеновский источник
US10431415B2 (en) * 2016-11-23 2019-10-01 General Electric Company X-ray tube ion barrier
EP3499545A1 (de) * 2017-12-12 2019-06-19 Siemens Healthcare GmbH Röntgenröhre
JP7112235B2 (ja) * 2018-04-12 2022-08-03 浜松ホトニクス株式会社 Ｘ線管

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE890246C (de) 1940-03-03 1953-09-17 Heinrich Dr Med Chantraine Roentgenroehre mit einer aus einer umlaufenden metallischen Fluessigkeit, z. B. Quecksilber, bestehenden Anode
US5052034A (en) 1989-10-30 1991-09-24 Siemens Aktiengesellschaft X-ray generator
US6185277B1 (en) 1998-05-15 2001-02-06 U.S. Philips Corporation X-ray source having a liquid metal target
US6477234B2 (en) * 2000-12-16 2002-11-05 Koninklijke Philips Electronics N.V. X-ray source having a liquid metal target
US6560313B1 (en) * 1999-11-18 2003-05-06 Koninklijke Philips Electronics N.V. Monochromatic X-ray source
US6647094B2 (en) * 2001-06-19 2003-11-11 Koninklijke Philips Electronics N.V. X-ray source provided with a liquid metal target

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19614222C1 (de) * 1996-04-10 1997-08-21 Siemens Ag Röntgenröhre mit ringförmiger Anode
JPH11339704A (ja) * 1998-05-29 1999-12-10 Tomohei Sakabe 回転対陰極ｘ線発生装置

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE890246C (de) 1940-03-03 1953-09-17 Heinrich Dr Med Chantraine Roentgenroehre mit einer aus einer umlaufenden metallischen Fluessigkeit, z. B. Quecksilber, bestehenden Anode
US5052034A (en) 1989-10-30 1991-09-24 Siemens Aktiengesellschaft X-ray generator
US6185277B1 (en) 1998-05-15 2001-02-06 U.S. Philips Corporation X-ray source having a liquid metal target
US6560313B1 (en) * 1999-11-18 2003-05-06 Koninklijke Philips Electronics N.V. Monochromatic X-ray source
US6477234B2 (en) * 2000-12-16 2002-11-05 Koninklijke Philips Electronics N.V. X-ray source having a liquid metal target
US6647094B2 (en) * 2001-06-19 2003-11-11 Koninklijke Philips Electronics N.V. X-ray source provided with a liquid metal target

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6947522B2 (en) * 2002-12-20 2005-09-20 General Electric Company Rotating notched transmission x-ray for multiple focal spots
US20040120463A1 (en) * 2002-12-20 2004-06-24 General Electric Company Rotating notched transmission x-ray for multiple focal spots
US20070258563A1 (en) * 2004-01-20 2007-11-08 Geoffrey Harding Anode Module for a Liquid Metal Anode X-Ray Source, and X-Ray Emitter Comprising an Anode Module
US7443958B2 (en) 2004-03-19 2008-10-28 Ge Homeland Protection, Inc. Electron window for a liquid metalanode, liquid metal anode, X-ray emitter and method for operating such an X-ray emitter of this type
US20070177715A1 (en) * 2004-03-19 2007-08-02 Geoffrey Harding Electron window for a liquid metalanode, liquid metal anode, x-ray emitter and method for operating such an x-ray emitter of this type
US7515688B2 (en) * 2004-03-30 2009-04-07 Ge Homeland Protection, Inc. Anode module for a liquid metal anode X-ray source, and X-ray emitter comprising an anode module
US7280639B2 (en) * 2004-06-25 2007-10-09 Siemens Aktiengesellschaft Rotary piston x-ray tube with the anode in a radially rotating section of the piston shell
US20050286684A1 (en) * 2004-06-25 2005-12-29 Mathias Hornig Rotary piston x-ray tube with the anode in a radially rotating section of the piston shell
US20060146985A1 (en) * 2004-11-19 2006-07-06 Thomas Deutscher Leakage radiation shielding arrangement for a rotary piston x-ray radiator
US7382865B2 (en) * 2004-11-19 2008-06-03 Siemens Aktiengesellschaft Leakage radiation shielding arrangement for a rotary piston x-ray radiator
US8983037B2 (en) 2009-09-30 2015-03-17 Koninklijke Philips N.V. Balancing of the rotary anode of an X-ray tube
DE102012203807A1 (de) * 2012-03-12 2013-09-12 Siemens Aktiengesellschaft Röntgenröhre
US9257255B2 (en) 2013-08-08 2016-02-09 Siemens Aktiengesellschaft Single-pole x-ray emitter
WO2016010448A1 (en) 2014-07-17 2016-01-21 Siemens Aktiengesellschaft Fluid injector for x-ray tubes and method to provide a liquid anode by liquid metal injection
US10192711B2 (en) 2014-07-17 2019-01-29 Siemens Aktiengesellschaft Fluid injector for X-ray tubes and method to provide a liquid anode by liquid metal injection
EP3926656A4 (de) * 2019-04-26 2022-05-04 EUV Labs Ltd. Röntgenstrahlquelle mit rotierendem flüssigmetallziel

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Publication number Publication date
DE10147473A1 (de) 2003-04-10
US20030058995A1 (en) 2003-03-27
DE10147473C2 (de) 2003-09-25

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